Paramedic National Registry Practice

A nasal cannula at 6 liters per minute delivers what percentage of oxygen to a patient?

1. 28%

2. 32%

3. 44%

4. 50%

The correct answer is: 44%

A nasal cannula set at 6 liters per minute typically delivers approximately 44% oxygen to a patient. This estimation is based on the principle that each liter of supplemental oxygen that a patient receives contributes roughly 4% to the overall oxygen saturation above the room air level, which is about 21%. When a nasal cannula is used, the effective percentage of oxygen delivered can be calculated as follows: starting from 21% (the baseline room air concentration), adding 4% for every liter of oxygen flow. Therefore, at 6 liters per minute, the calculation would be: 21% (room air) + (6 liters x 4%) = 21% + 24% = 45%. However, because there is a more effective mixing of the oxygen with the ambient air when using a nasal cannula, the actual delivered concentration is commonly rounded down due to physiological factors. Hence, it typically equates to about 44% in practical terms. It's important to remember that the percentage of oxygen delivered via a nasal cannula can vary depending on factors such as the patient's breathing pattern and the presence of any obstructions that might alter the flow.